Dozer是一個JavaBean到JavaBean之間的轉換工具。它就可以遞歸的將數(shù)據(jù)從一個對象復制到另一個對象溢吻。

Dozer的官方文檔：http://dozer.sourceforge.net/documentation/whymap.html
Dozer的github地址：https://github.com/DozerMapper/dozer

Dozer轉換好處：

• 如果兩個類型屬性名稱一致维费，不論類型是否一致。dozer都可以自動配置
• 如果類中有null property促王，dozer可以默認將屬性指為null犀盟，不會拋出nullPointerExeception異常。

Dozer整合項目（有三種：xml形式/注解配置/API配置）

引入jar

<dependency>
    <groupId>net.sf.dozer</groupId>
    <artifactId>dozer</artifactId>
    <version>5.4.0</version>
</dependency>

xml配置

• xml頭部文件

<?xml version="1.0" encoding="UTF-8"?>
<mappings xmlns="http://dozer.sourceforge.net" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://dozer.sourceforge.net  
       http://dozer.sourceforge.net/schema/beanmapping.xsd">

</mappings> 

xml中mapping配置（將a中對應的屬性名轉換為b中對應的屬性名蝇狼，<a>標簽轉換為<b>標簽）

<mapping>
        <class-a>com.qding.brick.pojo.biz.Project</class-a>
        <class-b>com.qding.openapi.call.stage.struct.Project</class-b>
        <field>
            <a>id</a>
            <b>projectId</b>
        </field>
        <field>
            <a>name</a>
            <b>projectName</b>
        </field>
        <field>
            <a>address</a>
            <b>addr</b>
        </field>
</mapping>

注：官網(wǎng)著重建議：在現(xiàn)實應用中阅畴，最好不要每次映射對象時都創(chuàng)建一個Mapper實例來工作，這樣會產(chǎn)生不必要的開銷迅耘。如果你不使用IoC容器（如：spring）來管理你的項目恶阴，那么，最好將Mapper定義為單例模式豹障。

• 測試：

Mapper mapper = new DozerBeanMapper();
DestinationObject destObject =  mapper.map(sourceObject, DestinationObject.class);

• 補充：單例模式例子

public class DozerMapperConstant {
    private static final Mapper mapper= new org.dozer.DozerBeanMapper();
    public static DozerBeanMapper getDozerBeanMapper() {
        return mapper;
    }
}

Mapper announcementDozerMapper =  DozerMapperConstant.dozerMapper;

API方式

import static org.dozer.loader.api.FieldsMappingOptions.*;
import static org.dozer.loader.api.TypeMappingOptions.*;

...

BeanMappingBuilder builder = new BeanMappingBuilder() {
      protected void configure() {
        mapping(Bean.class, Bean.class,
                TypeMappingOptions.oneWay(),
                mapId("A"),
                mapNull(true)
        )
                .exclude("excluded")
                .fields("src", "dest",
                        copyByReference(),
                        collectionStrategy(true, 
                            RelationshipType.NON_CUMULATIVE),
                        hintA(String.class),
                        hintB(Integer.class),
                        FieldsMappingOptions.oneWay(),
                        useMapId("A"),
                        customConverterId("id")
                )
                .fields("src", "dest",
                    customConverter("org.dozer.CustomConverter")
                );
      }
    };

使用

DozerBeanMapper mapper = new DozerBeanMapper();
mapper.addMapping(builder);

注解方式 （mapping自動注入）

a類

public class SourceBean {

    private Long id;

    private String name;

    @Mapping("binaryData")
    private String data;

    @Mapping("pk")
    public Long getId() {
        return this.id;
    }

    public String getName() {
        return this.name;
    }
}

b類

public class TargetBean {

    private String pk;

    private String name;

    private String binaryData;

    public void setPk(String pk) {
        this.pk = pk;
    }

    public void setName(String name) {
        this.name = name;
    }
}